drm/i915: Avoid potential division-by-zero in computing CS timestamp period (d194314d) · Commits · 戴 / test

Since we use a HW readback or estimation of the CS timestamp frequency, sometimes it may result in 0. Avoid the division-by-zero in computing its reciprocal, the timestamp period. Signed-off-by:

Chris Wilson <chris@chris-wilson.co.uk> Acked-by:

Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200216161746.500258-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/intel_device_info.c

+11 −7

Original line number	Diff line number	Diff line
		@@ -1044,14 +1044,18 @@ void intel_device_info_runtime_init(struct drm_i915_private *dev_priv)
		}

		/* Initialize command stream timestamp frequency */
		runtime->cs_timestamp_frequency_khz = read_timestamp_frequency(dev_priv);
		runtime->cs_timestamp_frequency_khz =
		read_timestamp_frequency(dev_priv);
		if (runtime->cs_timestamp_frequency_khz) {
		runtime->cs_timestamp_period_ns =
		div_u64(1e6, runtime->cs_timestamp_frequency_khz);
		drm_dbg(&dev_priv->drm,
		"CS timestamp wraparound in %lldms\n",
		div_u64(mul_u32_u32(runtime->cs_timestamp_period_ns, S32_MAX),
		div_u64(mul_u32_u32(runtime->cs_timestamp_period_ns,
		S32_MAX),
		USEC_PER_SEC));
		}
		}

		void intel_driver_caps_print(const struct intel_driver_caps *caps,
		struct drm_printer *p)

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